It has been known that H2, that is, molecular hydrogen, has a function for selectively detoxifying a hydroxyl radical .OH of active oxygen that is harmful to the body. In recent years, by taking this function into consideration, a product formed by dissolving a hydrogen gas into water (referred to as “hydrogen water”), an article formed by dissolving a hydrogen gas in an infusion or a storage liquid for use in an infusion treatment, a suction-type device for allowing a hydrogen-mixed gas to be directly taken into the alveoli through breathing, etc. have been utilized.
Among these, with respect the suction-type device for a hydrogen gas, animal experiments or clinical trials have been carried out by using a mixed gas having a hydrogen concentration of less than 4% so that a superior effect for selectively eliminating a hydroxy radical having the highest oxidizing strength of active oxygen generated in the body has been found out. In this case, however, the value of the hydrogen concentration of 4% or less is determined so as to avoid the following ranges from the safety point of view, since with respect to an explosion-hazard range of a hydrogen-mixed gas, an explosion or a combustion tends to occur as a mixed gas when a catching fire point (igniting point) is located between a lower-limit mixed gas ratio of 4.1% and an upper-limit mixed gas ratio of 74.2% in the case of a mixed gas between air and hydrogen, as well as between a lower-limit mixed gas ratio of 4.65% and a higher-limit mixed gas ratio of 93.3% in the case of a mixed gas between oxygen and hydrogen.
Therefore, various suction tests using a hydrogen-mixed gas having a hydrogen gas concentration of less than 4% are carried out in accordance with a disaster-prevention safety standard for preventing an explosion-combustion accident in the industrial field centered on the energy field, and its concentration is not necessarily an optimal value in the human body, and there are still unexplored fields left in the aspects of animal experiments, clinical tests or actual treatments and preventions of various diseases so as to confirm the possibility of various functional effects by the application of a hydrogen-mixed gas exceeding the concentration of 4%, and this implicit limitation of 4% or less has caused one reason of intervening the progress of medicine.
Moreover, in the case of a device disclosed by JP-A No. 2009-5881 that is supposed to desirably set the hydrogen gas concentration to be sucked, the device fails to ensure an oxygen partial pressure of 21% in concentration required for daily breathing of a human body, and if the hydrogen concentration is set to 30% in the device of JP-A No. 2009-5881, oxygen needs to be obtained from the rest of 70% of air, with the result that the total oxygen concentration becomes an oxygen concentration of about 14.7%, which is lower than the lower limit value of an oxygen concentration required for the human body or lower than the lower limit value of the safety standard of 18%, causing suffocation due to lack of oxygen. Moreover, no safety measures have been taken into consideration against the fact that the explosion lower limit concentration of hydrogen gas is exceeded, with the result that if a discharge is generated in the periphery of the corresponding portion due to static electricity or the like, there is a risk of an explosion-combustion accident; therefore, the device of JP-A No. 2009-5881 is considered to be unfinished as a practical device.
Furthermore, another method has been utilized in which as one of folk remedies, a mixed gas having 66% of hydrogen and 33% of oxygen obtained by electrolyzing water is sucked from nostrils by using a cannula; however, the hydrogen gas concentration of 66% corresponds to a concentration inside the introduction tube from a supply side to the nostril cannula, with the result that the hydrogen gas is actually mixed with ambient air so that the hydrogen gas actually sucked from the nostrils into the bronchi has a hydrogen gas concentration of 4% or less, and on the assumption from its flowing rate, the hydrogen gas concentration is normally less than 1% in most cases.
Furthermore, most of suction treatments and treatment tests of a hydrogen-mixed gas currently put into practice are assumed to be applied to a person having a nearly normal lung function, and for example, persons having diseases, such as viral pneumonia, bacterial pneumonia or the like, are out of the subject, and as the suction treatment, no method other than the sole use of a hydrogen-mixed gas has been assumed.